Nib retaining assembly for a writing instrument

Abstract

A nib retaining assembly for a writing instrument to hold a capillary writing element or nib of small cross-sectional dimension in position against writing pressure, the nib retaining assembly including a nib receiving main longitudinal passageway formed by offset portions through which the capillary element extends. The capillary element is held by light staking within an axial bore of a nib holder which, in turn, is inserted into a seat at one end of the passageway. Because of the passageway offset portions and an intermediate camming surface, a capillary element inserted into the passageway is deflected around an internal shoulder so as to be forced into frictional engagement with the passageway walls to hold the small nib in writing position without disturbing the capillary action. In one embodiment of the invention, the passageway is defined by a nib retaining adapter inserted into a seat in the barrel; while in another embodiment the passageway is defined by the tubular barrel of the instrument. A single nib retaining assembly will accommodate nibs of many different diameters.

I claim: 
     
       1. A writing instrument, comprising: an elongated hollow barrel having an internal chamber and a front end portion shaped to afford a forwardly opening annular seat, the barrel being provided with a longitudinal passageway extending between the chamber and the annular seat and having a transversely extending portion extending into the passageway to form an abutment having a forwardly facing, rearwardly inclined surface, the abutment being positioned rearwardly of the seat and partially obstructing said longitudinal passageway to afford a smaller constricted passageway; an elongate reservoir of absorbent material positioned in the chamber of the barrel to receive a quantity of writing fluid; a separable nib holder having a longitudinal nib-supporting bore therethrough and an inner body portion shaped to frictionally fit within the annular seat, the inner body portion and the bore being positioned in longitudinal alignment with said abutment and the inner ends of the body portion and bore being closely spaced from the abutment when the nib holder is fully seated in the annular seat; and an elongate flexible plastic nib extending through the bore of the nib holder and being deflected by the abutment surface through the constricted passageway into the reservoir in the barrel without any cutting or splitting of said nib by the abutment, the nib having an outer end portion provided with a writing end exposed forwardly of the nib holder, an inner end portion extending through the constricted passageway to the reservoir for receiving writing fluid, and an intermediate portion positioned against said abutment and between said abutment and said inner end of said inner body portion to prevent movement of the nib inwardly of the passageway when the nib holder is fully seated in the annular seat of the barrel, the axes of said outer and inner end portions being in laterally offset relation and the axis of the intermediate portion extending transversely of the axes of said outer and inner end portions, the constricted passageway having a cross-section of a size to accommodate a plurality of nib sizes with a single barrel structure. 
     
     
       2. A writing instrument as specified in claim 1, in which the nib is resiliently flexible and the inner end portion of the nib extending rearwardly through the passageway of the barrel frictionally engages the barrel to augment the securement of the nib in writing position. 
     
     
       3. A writing instrument as specified in claim 2, in which the abutment has a free end having an angular shoulder, said shoulder being positioned to bear against the nib between the intermediate portion and the inner end portion. 
     
     
       4. A writing instrument as in claim 1, in which the nib holder has a shoulder bearing against the front end portion of the barrel when the nib holder is fully seated in the annular barrel seat to afford the spacing for the nib intermediate portion. 
     
     
       5. In a writing instrument having an elongated hollow barrel provided with an internal chamber to receive an elongated reservoir of absorbent material for a quantity of writing fluid, the barrel being closed at one end portion and open at the other end portion to afford an annular barrel seat, a nib retaining assembly, comprising: an adaptor member shaped to frictionally fit within said barrel seat, the adaptor member having a longitudinal passageway therethrough opening into the barrel chamber and being shaped at its forward end to afford an adaptor seat, said adaptor member further having a transversely extending abutment positioned rearwardly of said adaptor seat and partially obstructing said passageway to form a smaller constricted passageway, the abutment having a forwardly facing, rearwardly inclined surface; a separable nib holder having a longitudinal nib-supporting bore therethrough and an inner body portion shaped to frictionally fit within the adaptor seat, the inner body portion and the bore each being positioned in longitudinal alignment with the abutment of the adaptor member and each having an inner end closely spaced from the abutment when the nib holder is fully seated in the adaptor seat; and an elongate flexible plastic nib extending through the bore of the nib holder and being deflected by the abutment surface through the constricted passageway of the adaptor into the reservoir of the barrel without any cutting or splitting of said nib by the abutment, the nib having an outer end portion provided with a writing end exposed forwardly of the nib holder, an inner end portion extending through the constricted passageway to the reservoir for receiving writing fluid, and an intermediate portion positioned against said abutment and between said abutment and the inner end of said body portion to prevent movement of the nib inwardly of the passageway when the nib holder is fully seated in the adaptor seat, the axes of said outer and inner end portions being in laterally offset relation and the axis of the intermediate portion extending transversely of the axes of said outer and inner end portions, the constricted passageway having a cross-section of a size to accommodate a plurality of nib sizes with a single adaptor member. 
     
     
       6. A nib retaining assembly as specified in claim 5, in which the nib is resiliently flexible and the inner end portion of the nib extending rearwardly through the constricted passageway frictionally engages the adaptor to augment the securement of the nib in writing position. 
     
     
       7. A nib retaining assembly as specified in claim 6, in which the abutment has a free end having an angular shoulder, said shoulder being positioned to bear against the nib between the intermediate portion and the inner end portion. 
     
     
       8. The nib retaining assembly as specified in claim 5, in which the nib holder has a shoulder bearing against the forward end of the adaptor member when the nib holder is fully seated in the adaptor seat to afford the spacing for the nib intermediate portion. 
     
     
       9. The nib retaining assembly as in claim 5 in which the nib holder is lightly staked to the portion of the nib extending through the bore to hold the nib and nib holder together during assembly into the adaptor member. 
     
     
       10. The nib retaining assembly as in claim 5 in which the cross-sectional width of the nib is in the range of 0.5 mm to 3.0 mm. 
     
     
       11. The nib retaining assembly as in claim 5 in which the cross-sectional width of the nib is in the range of 0.5 mm to 1.0 mm.